Photodissociation dynamics of jet-cooled H2O and D2O in the non-Franck–Condon regime: Relative absorption cross sections and product state distributions at 193 nm

1997 ◽  
Vol 107 (16) ◽  
pp. 6123-6135 ◽  
Author(s):  
David F. Plusquellic ◽  
Ondrej Votava ◽  
David J. Nesbitt
Keyword(s):  
Cross Sections ◽  
Product State ◽  
Absorption Cross ◽  
Relative Absorption ◽  
193 Nm ◽  
Franck Condon

scholarly journals Ultraviolet absorption cross sections of carbonyl sulfide isotopologues OC<sup>32</sup>S, OC<sup>33</sup>S, OC<sup>34</sup>S and O<sup>13</sup>CS: isotopic fractionation in photolysis and atmospheric implications

2011 ◽  
Vol 11 (19) ◽  
pp. 10293-10303 ◽  
Author(s):  
S. Hattori ◽  
S. O. Danielache ◽  
M. S. Johnson ◽  
J. A. Schmidt ◽  
H. G. Kjaergaard ◽  
...  
Keyword(s):  
Cross Sections ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
High Energy ◽  
Ultraviolet Absorption ◽  
Absorption Cross ◽  
Rare Isotopes ◽  
Mass Dependent ◽  
Franck Condon ◽  
Energy Side

Abstract. We report measurements of the ultraviolet absorption cross sections of OC32S, OC33S, OC34S and O13CS from 195 to 260 nm. The OCS isotopologues were synthesized from isotopically-enriched elemental sulfur by reaction with carbon monoxide. The measured cross section of OC32S is consistent with literature spectra recorded using natural abundance samples. Relative to the spectrum of the most abundant isotopologue, substitution of heavier rare isotopes has two effects. First, as predicted by the reflection principle, the Gaussian-based absorption envelope becomes slightly narrower and blue-shifted. Second, as predicted by Franck-Condon considerations, the weak vibrational structure is red-shifted. Sulfur isotopic fractionation constants (33ε, 34ε) as a function of wavelength are not highly structured, and tend to be close to zero on average on the high energy side and negative on the low energy side. The integrated photolysis rate of each isotopologue at 20 km, the approximate altitude at which most OCS photolysis occurs, was calculated. Sulfur isotopic fractionation constants at 20 km altitude are (−3.7 ± 4.5)‰ and (1.1 ± 4.2)‰ for 33ε and 34ε, respectively, which is inconsistent with the previously estimated large fractionation of over 73‰ in 34ε. This demonstrates that OCS photolysis does not produce sulfur isotopic fractionation of more than ca. 5‰, suggesting OCS may indeed be a significant source of background stratospheric sulfate aerosols. Finally, the predicted isotopic fractionation constant for 33S excess (33E) in OCS photolysis is (−4.2 ± 6.6)‰, and thus photolysis of OCS is not expected to be the source of the non-mass-dependent signature observed in modern and Archaean samples.

scholarly journals Absorption cross sections for water vapor from 183 to 193 nm

1997 ◽  
Vol 24 (17) ◽  
pp. 2195-2198 ◽  
Author(s):  
Christopher A. Cantrell ◽  
Audrey Zimmer ◽  
Geoffrey S. Tyndall
Keyword(s):  
Water Vapor ◽  
Cross Sections ◽  
Absorption Cross ◽  
193 Nm

scholarly journals Ultraviolet absorption cross sections of carbonyl sulfide isotopologues OC<sup>32</sup>S, OC<sup>33</sup>S, OC<sup>34</sup>S and O<sup>13</sup>CS: isotopic fractionation in photolysis and atmospheric implications

2011 ◽  
Vol 11 (7) ◽  
pp. 20487-20520 ◽  
Author(s):  
S. Hattori ◽  
S. O. Danielache ◽  
M. S. Johnson ◽  
J. A. Schmidt ◽  
H. G. Kjaergaard ◽  
...  
Keyword(s):  
Cross Sections ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
High Energy ◽  
Ultraviolet Absorption ◽  
Absorption Cross ◽  
Rare Isotopes ◽  
Mass Dependent ◽  
Franck Condon ◽  
Energy Side

Abstract. We report measurements of the ultraviolet absorption cross sections of OC32S, OC33S, OC34S and O13CS from 195 to 260 nm. The OCS isotopologues were synthesized from isotopically-enriched elemental sulfur by reaction with carbon monoxide. The measured cross section of OC32S is consistent with literature spectra recorded using natural abundance samples. Relative to the spectrum of the most abundant isotopologue, substitution of heavier rare isotopes has two effects. First, as predicted by the reflection principle, the Gaussian-based absorption envelope becomes slightly more narrow and blue-shifted. Second, as predicted by Franck-Condon considerations, the weak vibrational structure is red-shifted. Sulfur isotopic fractionation constants (33ε, 34ε) as a function of wavelength are not highly structured, and tend to be close to zero on average on the high energy side and negative on the low energy side. Since OCS photolysis occurs in the lower stratosphere, the integrated photolysis rate of each isotopologue at 20 km was calculated. Sulfur isotopic fractionation constants at 20 km altitude are (−3.7 ± 4.5) ‰ and (1.1 ± 4.2) ‰ for 33ε and 34ε, respectively, which is inconsistent with the previously estimated large fractionation of over 73 ‰ in 34ε. This demonstrates that OCS photolysis does not produce sulfur isotopic fractionation of more than ca. 5 ‰, suggesting OCS may be the source of background stratospheric sulfate aerosols. Finally, the predicted isotopic fractionation constant for 33S excess (33E) in OCS photolysis is (−4.2 ± 6.6) ‰, and thus photolysis of OCS is not expected to be the source of the non-mass-dependent signature observed in modern and Archaean samples.

scholarly journals Correction to “Absorption cross sections for water vapor from 183 to 193 nm”

1997 ◽  
Vol 24 (21) ◽  
pp. 2687-2687 ◽  
Author(s):  
Christopher A. Cantrell ◽  
Audrey Zimmer ◽  
Geoffrey S. Tyndall
Keyword(s):  
Water Vapor ◽  
Cross Sections ◽  
Absorption Cross ◽  
193 Nm

Spectroscopy Fundamentals

2017 ◽  
Author(s):  
Kelly Chance ◽  
Randall V. Martin
Keyword(s):  
Vibrational Spectroscopy ◽  
Cross Sections ◽  
Nuclear Spin ◽  
Electronic Spectroscopy ◽  
Rotational Spectroscopy ◽  
Absorption Cross ◽  
Transfer Processes ◽  
Atmospheric Spectroscopy ◽  
Quantitative Spectroscopy ◽  
Broad Overview

This chapter provides a broad overview of the spectroscopic principles required in order to perform quantitative spectroscopy of atmospheres. It couples the details of atmospheric spectroscopy with the radiative transfer processes and also with the assessment of rotational, vibrational, and electronic spectroscopic measurements of atmospheres. The principles apply from line-resolved measurements (chiefly microwave through infrared) through ultraviolet and visible measurements employing absorption cross sections developed from individual transitions. The chapter introduces Einstein coefficients before in turn discussing rotational spectroscopy, vibrational spectroscopy, nuclear spin, and electronic spectroscopy.

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